This 3Com product has many functions: router, firewall, adsl modem, wireless access point, 4 port switch. 3Com chose to give two names to its products: a name for the market (as the long name in the title), which identifies the purpose of the product and is not changed when a new model replaces the older one, and a model name, a number which identifies the specific model.
The "ADSL" term in the name is particularly useful to specify that it's a adsl modem too, with a RJ-11 port that would connect the router directly to the phone line, through a RJ-11 cable, just like any adsl modem; in fact I found several routers that were capable of routing the adsl signal but were equipped with a RJ-45 port instead of a RJ-11 port: they were not DSL modems and needed to be connected to an external DSL modem. Checking the rear of the product, maybe on the user guide, can help making sure the router is a DSL modem too.
I will review two 3Com OfficeConnect ADSL Wireless 54 Mbps 11g Firewall Router models, the older 3CRWDR100A-72 and the newer 3CRWDR101A-75.